This document describes the Generalized Moving Peaks Benchmark (GMPB) that generates continuous dynamic optimization problem instances. The landscapes generated by GMPB are constructed by assembling several components with a variety of controllable characteristics ranging from unimodal to highly multimodal, symmetric to highly asymmetric, smooth to highly irregular, and various degrees of variable interaction and ill-conditioning. In this document, we explain how these characteristics can be generated by different parameter settings of GMPB. The MATLAB source code of GMPB is also explained. This document forms the basis for a range of competitions on Evolutionary Continuous Dynamic Optimization in the upcoming well-known conferences.